The Martian

Remember those old math questions you had in Algebra class? Where water is entering a container at a certain rate and leaving at a different rate and you need to figure out when it’ll be empty? Well, that concept is critical to the “Mark Watney doesn’t die” project I’m working on.

I need to create calories. And I need enough to last four years. I figure if I don’t get rescued by Ares 4, I’m dead anyway. So that’s my target: four years.

I have plenty of multivitamins; over double what I need. And there’s five times the minimum protein in each food pack, so careful rationing of portions takes care of my protein needs for at least four years. My general nutrition is taken care of. I just need calories.

I need 1500 calories every day. I have 400 days of food to start off with. So how many calories do I need to generate per day along the entire time period to stay alive for 1400 days total (the time till Ares 4 arrives)?

I’ll spare you the math. The answer is a cool 1000. I need to create 1000 calories per day with my farming efforts to survive until Ares 4 gets here. Actually, a little more than that, because it’s sol 25 right now and I haven’t actually planted anything yet.

With my 62 square meters of farmland, I’ll be able to create about 288 calories per day. I need to bring that up to 1000. I need four times my current plan’s production to survive.

I need more surface area for farming, and I need water to hydrate the soil. So let’s take the problems one at a time.

How much farmland can I really make?

There are 92 square meters in the Hab. Let’s say I could make use of all of it.

Also, there are five unused bunks. Let’s say I put soil in on them, too. They’re 2 square meters each, giving me 10 more square meters. So we’re up to 102.

The Hab has three lab tables, each about 2 square meters. I want to keep one for my own use, leaving two for the cause. That’s another four square meters, bringing the total to 106.

I have two Martian rovers. They have pressure seals, allowing the occupants to drive in ease, without spacesuits, as they spent long periods traversing the surface. They’re too cramped to plant crops in, and I want to be able to drive them around anyway. But both rovers have an emergency pop-tent.

There are a lot of problems with using pop-tents as farmland, but they have 10 square meters of floor space each. Presuming I can overcome the problems, they net me another 20 square meters, bringing my farmland up to 126.

126 square meters of farmable land. That’s something to work with. Not nearly enough water to moisten the soil, but like I said, one thing at a time.

The next thing to consider is how efficient I can be in growing potatoes. I based my crop yield estimates on the potato industry back on Earth. But potato farmers aren’t in a desperate race for survival like I am. Can I get a better yield?

For starters, I can give attention to each individual plant. I can trim them and keep them healthy and not interfering with each other. Also, as their flowering bodies breach the surface, I can replant them deeper, then plant younger plants above them. For normal potato farmers, it’s not worth doing because they’re working with literally millions of potato plants.

Also, this sort of farming annihilates the soil. Any farmer doing it would turn their land into a dust bowl within 12 years. It’s not sustainable. But who gives a shit? I just need to survive four years.

I estimate I can get 50% higher yield by using these tactics. And with the 126 square meter farmland (just over double the 62 square meters I have) it works out to be over 900 calories per day.

That’s real progress. I’d still be in danger of starvation, but it gets me in the range of survival. I might be able to make it by nearly starving but not quite dying. I could reduce my caloric use by minimizing manual labor. I could set the temperature of the Hab higher than normal, meaning my body expends less energy keeping its temperature. I could cut off an arm and eat it, gaining me valuable calories and reducing my overall caloric need.

No, not really.

So let’s say I could clear up that much farmland. Seems reasonable. Where do I get the water? To go from 62 to 126 square meters of farmland at 10cm deep, I’ll need 6.4 more cubic meters of soil (more shoveling, whee!) and that’ll need over 250 liters of water.

The 50L I have is for me to drink if the Water Reclaimer breaks. So I’m 250L short of my 250L goal.

Bleh. I’m going to bed.

LOG ENTRY: SOL 26

It was a back-breaking yet productive day.

I was sick of thinking, so instead of trying to figure out where I’ll get 250L of water, I did some manual labor. I need to get a whole assload more soil in to the Hab, even if it is dry and useless right now.

I got a cubic meter in before getting exhausted.